Import BSDDB 4.7.25 (as of svn r89086)

examples_c/csv/query.c

@@ -0,0 +1,241 @@
+/*-
+ * See the file LICENSE for redistribution information.
+ *
+ * Copyright (c) 2005,2008 Oracle.  All rights reserved.
+ *
+ * $Id: query.c 63573 2008-05-23 21:43:21Z trent.nelson $
+ */
+
+#include "csv.h"
+#include "csv_local.h"
+#include "csv_extern.h"
+
+static int query_by_field(char *);
+static int query_fieldlist(char *);
+static int query_help(char *);
+static int query_usage(void);
+
+typedef struct _cmdtab {
+	char	*cmd;			/* Command name */
+	int	(*f)(char *);		/* Underlying function. */
+	char	*help;			/* Help message. */
+} CMDTAB;
+
+static CMDTAB cmdtab[] = {
+	{ "?",
+		query_help,
+		"?\t\tDisplay help screen" },
+	{ "exit",
+		NULL,
+		"exit\t\tExit program" },
+	{ "fields",
+		query_fieldlist,
+		"fields\t\tDisplay list of field names" },
+	{ "help",
+		query_help,
+		"help\t\tDisplay help screen" },
+	{ "quit",
+		NULL,
+		"quit\t\tExit program" },
+	{ NULL,
+		query_by_field,
+    "field[op]value\tDisplay fields by value (=, !=, <, <=, >, >=, ~, !~)" },
+	{ NULL,		NULL,		NULL }
+};
+
+/*
+ * query_interactive --
+ *	Allow the user to interactively query the database.
+ */
+int
+query_interactive()
+{
+	int done;
+	char *p, input[256];
+
+	for (;;) {
+		printf("Query: ");
+		(void)fflush(stdout);
+		if (fgets(input, sizeof(input), stdin) == NULL) {
+			printf("\n");
+			if (ferror(stdin)) {
+				dbenv->err(dbenv, errno,
+				    "error occurred reading from stdin");
+				return (1);
+			}
+			break;
+		}
+		if ((p = strchr(input, '\n')) == NULL) {
+			dbenv->errx(dbenv, "input buffer too small");
+			return (1);
+		}
+		*p = '\0';
+		if (query(input, &done) != 0)
+			return (1);
+		if (done != 0)
+			break;
+	}
+	return (0);
+}
+
+/*
+ * query --
+ *	Process a query.
+ */
+int
+query(char *cmd, int *donep)
+{
+	CMDTAB *p;
+
+	if (donep != NULL)
+		*donep = 0;
+
+	for (p = cmdtab; p->cmd != NULL; ++p)
+		if (p->cmd != NULL &&
+		    strncasecmp(cmd, p->cmd, strlen(p->cmd)) == 0)
+			break;
+
+	if (p->cmd == NULL)
+		return (query_by_field(cmd));
+
+	if (p->f == NULL) {
+		if (donep != NULL)
+			*donep = 1;
+		return (0);
+	}
+
+	return (p->f(cmd));
+}
+
+/*
+ * query_by_field --
+ *	Query the primary database by field.
+ */
+static int
+query_by_field(char *input)
+{
+	OPERATOR operator;
+	size_t len;
+	char *field, *op, *value;
+
+	/*
+	 * We expect to see "field [op] value" -- figure it out.
+	 *
+	 * Skip leading whitespace.
+	 */
+	while (isspace(*input))
+		++input;
+
+	/*
+	 * Find an operator, and it better not start the string.
+	 */
+	if ((len = strcspn(field = input, "<>!=~")) == 0)
+		return (query_usage());
+	op = field + len;
+
+	/* Figure out the operator, and find the start of the value. */
+	switch (op[0]) {
+	case '~':
+		operator = WC;
+		value = op + 1;
+		break;
+	case '!':
+		if (op[1] == '=') {
+			operator = NEQ;
+			value = op + 2;
+			break;
+		}
+		if (op[1] == '~') {
+			operator = NWC;
+			value = op + 2;
+			break;
+		}
+		return (query_usage());
+	case '<':
+		if (op[1] == '=') {
+			operator = LTEQ;
+			value = op + 2;
+		} else {
+			operator = LT;
+			value = op + 1;
+		}
+		break;
+	case '=':
+		operator = EQ;
+		if (op[1] == '=')
+			value = op + 2;
+		else
+			value = op + 1;
+		break;
+	case '>':
+		if (op[1] == '=') {
+			operator = GTEQ;
+			value = op + 2;
+		} else {
+			operator = GT;
+			value = op + 1;
+		}
+		break;
+	default:
+		return (query_usage());
+	}
+
+	/* Terminate the field name, and there better be a field name. */
+	while (--op > input && isspace(*op))
+		;
+	if (op == input)
+		return (query_usage());
+	op[1] = '\0';
+
+	/* Make sure there is a value field. */
+	while (isspace(*value))
+		++value;
+	if (*value == '\0')
+		return (query_usage());
+
+	return (DbRecord_search_field_name(field, value, operator));
+}
+
+/*
+ * query_fieldlist --
+ *	Display list of field names.
+ */
+static int
+query_fieldlist(char *input)
+{
+	DbField *f;
+
+	input = input;				/* Quiet compiler. */
+
+	for (f = fieldlist; f->name != NULL; ++f)
+		printf("field %3d: %s\n", f->fieldno, f->name);
+	return (0);
+}
+
+/*
+ * query_help --
+ *	Query command list.
+ */
+static int
+query_help(char *input)
+{
+	CMDTAB *p;
+
+	input = input;				/* Quiet compiler. */
+
+	printf("Query commands:\n");
+	for (p = cmdtab; p->help != NULL; ++p)
+		printf("\t%s\n", p->help);
+	return (0);
+}
+
+/*
+ * query_usage --
+ *	Query usage message.
+ */
+static int
+query_usage(void)
+{
+	fprintf(stderr, "%s: query syntax error\n", progname);
+	return (query_help(NULL));
+}